中英文献 超声波测距仪1.docx

1、Ultrasonic distance meter Document Type and Number:United States Patent 5442592 Abstract:An ultrasonic distance meter cancels out the effects of temperature and humidity variations by including a measuring unit and a reference unit. In each of the units, a repetitive series of pulses is generated, e

2、ach having a repetition rate directly related to the respective distance between an electroacoustic transmitter and an electroacoustic receiver. The pulse trains are provided to respective counters, and the ratio of the counter outputs is utilized to determine the distance being measured. Publicatio

3、n Date:08/15/1995 Primary Examiner:Lobo, Ian J.一、BACKGROUND OF THE INVENTION This invention relates to apparatus for the measurement of distance and, more particularly, to such apparatus which transmits ultrasonic waves between two points. Precision machine tools must be calibrated. In the past, thi

4、s has been accomplished utilizing mechanical devices such as calipers, micrometers, and the like. However, the use of such devices does not readily lend itself to automation techniques. It is known that the distance between two points can be determined by measuring the propagation time of a wave tra

5、velling between those two points. One such type of wave is an ultrasonic, or acoustic, wave. When an ultrasonic wave travels between two points, the distance between the two points can be measured by multiplying the transit time of the wave by the wave velocity in the medium separating the two point

6、s. It is therefore an object of the present invention to provide apparatus utilizing ultrasonic waves to accurately measure the distance between two points. When the medium between the two points whose spacing is being measured is air, the sound velocity is dependent upon the temperature and humidit

7、y of the air. It is therefore a further object of the,present invention to provide apparatus of the type described which is independent of temperature and humidity variations. 二、SUMMARY OF THE INVENTION The foregoing and additional objects are attained in accordance with the principles of this inven

8、tion by providing distance measuring apparatus which includes a reference unit and a measuring unit. The reference and measuring units are the same and each includes an electroacoustic transmitter and an electroacoustic receiver. The spacing between the transmitter and the receiver of the reference

9、unit is a fixed reference distance, whereas the spacing between the transmitter and receiver of the measuring unit is the distance to be measured. In each of the units, the transmitter and receiver are coupled by a feedback loop which causes the transmitter to generate an acoustic pulse which is rec

10、eived by the receiver and converted into an electrical pulse which is then fed back to the transmitter, so that a repetitive series of pulses results. The repetition rate of the pulses is inversely related to the distance between the transmitter and the receiver. In each of the units, the pulses are

11、 provided to a counter. Since the reference distance is known, the ratio of the counter outputs is utilized to determine the desired distance to be measured. Since both counts are identically influenced by temperature and humidity variations, by taking the ratio of the counts, the resultant measurem

12、ent becomes insensitive to such variations. 三、BRIEF DESCRIPTION OF THE DRAWINGS The foregoing will be more readily apparent upon reading the following description in conjunction with the drawing in which the single FIGURE schematically depicts apparatus constructed in accordance with the principles

13、of this invention. 四、DETAILED DESCRIPTION Referring now to the drawing, there is shown a measuring unit 10 and a reference unit 12, both coupled to a utilization means 14. The measuring unit 10 includes an electroacoustic transmitter 16 and an electroacoustic receiver 18. The transmitter 16 includes

14、 piezoelectric material 20 sandwiched between a pair of electrodes 22 and 24. Likewise, the receiver 18 includes piezoelectric material 26 sandwiched between a pair of electrodes 28 and 30. As is known, by applying an electric field across the electrodes 22 and 24, stress is induced in the piezoelec

15、tric material 20. If the field varies, such as by the application of an electrical pulse, an acoustic wave 32 is generated. As is further known, when an acoustic wave impinges upon the receiver 18, this induces stress in the piezoelectric material 26 which causes an electrical signal to be generated

16、 across the electrodes 28 and 30. Although piezoelectric transducers have been illustrated, other electroacoustic devices may be utilized, such as, for example, electrostatic, electret or electromagnetic types. As shown, the electrodes 28 and 30 of the receiver 18 are coupled to the input of an ampl

17、ifier 34, whose output is coupled to the input of a detector 36. The detector 36 is arranged to provide a signal to the pulse former 38 when the output from the amplifier 34 exceeds a predetermined level. The pulse former 38 then generates a trigger pulse which is provided to the pulse generator 40.

18、 In order to enhance the sensitivity of the system, the transducers 16 and 18 are resonantly excited. There is accordingly provided a continuous wave oscillator 42 which provides a continuous oscillating signal at a fixed frequency, preferably the resonant frequency of the transducers 16 and 18. Thi

19、s oscillating signal is provided to the modulator 44. To effectively excite the transmitter 16, it is preferable to provide several cycles of the resonant frequency signal, rather than a single pulse or single cycle. Accordingly, the pulse generator 40 is arranged, in response to the application the

20、reto of a trigger pulse, to provide a control pulse to the modulator 44 having a time duration equal the time duration of a predetermined number of cycles of the oscillating signal from the oscillator 42. This control pulse causes the modulator 44 to pass a “burst“ of cycles to excite the transmitte

21、r 16. When electric power is applied to the described circuitry, there is sufficient noise at the input to the amplifier 34 that its output triggers the pulse generator 40 to cause a burst of oscillating cycles to be provided across the electrodes 22 and 24 of the transmitter 16. The transmitter 16

22、accordingly generates an acoustic wave 32 which impinges upon the receiver 18. The receiver 18 then generates an electrical pulse which is applied to the input of the amplifier 34, which again causes triggering of the pulse generator 40. This cycle repeats itself so that a repetitive series of trigg

23、er pulses results at the output of the pulse former 38. This pulse train is applied to the counter 46, as well as to the pulse generator 40. The transmitter 16 and the receiver 18 are spaced apart by the distance “D“ which it is desired to measure. The propagation time “t“ for an acoustic wave 32 tr

24、avelling between the transmitter 16 and the receiver 18 is given by: t=D/V s where V s is the velocity of sound in the air between the transmitter 16 and the receiver 18. The counter 46 measures the repetition rate of the trigger pulses, which is equal to 1/t. Therefore, the repetition rate is equal

25、 to V s /D. The velocity of sound in air is a function of the temperature and humidity of the air, as follows: #EQU1# where T is the temperature, p is the partial pressure of the water vapor, H is the barometric pressure, w and a are the ratio of constant pressure specific heat to constant volume sp

26、ecific heat for water vapor and dry air, respectively. Thus, although the repetition rate of the trigger pulses is measured very accurately by the counter 46, the sound velocity is influenced by temperature and humidity so that the measured distance D cannot be determined accurately. In accordance w

27、ith the principles of this invention, a reference unit 12 is provided. The reference unit 12 is of the same construction as the measuring unit 10 and therefore includes an electroacoustic transmitter 50 which includes piezoelectric material 52 sandwiched between a pair of electrodes 54 and 56, and a

28、n electroacoustic receiver 58 which includes piezoelectric material 60 sandwiched between a pair of electrodes 62 and 64. Again, transducers other than the piezoelectric type can be utilized. The transmitter 50 and the receiver 58 are spaced apart a known and fixed reference distance “D R “. The ele

29、ctrodes 62 and 64 are coupled to the input of the amplifier 66, whose output is coupled to the input of the detector 68. The output of the detector 68 is coupled to the pulse former 70 which generates trigger pulses. The trigger pulses are applied to the pulse generator 72 which controls the modulat

30、or 74 to pass bursts from the continuous wave oscillator 76 to the transmitter 50. The trigger pulses from the pulse former 70 are also applied to the counter 78. Preferably, all of the transducers 16, 18, 50 and 58 have the same resonant frequency. Therefore, the oscillators 42 and 76 both operate

31、at that frequency and the pulse generators 40 and 72 provide equal width output pulses. In usage, the measuring unit 10 and the reference unit 12 are in close proximity so that the sound velocity in both of the units is the same. Although the repetition rates of the pulses in the measuring unit 10 a

32、nd the reference unit 12 are each temperature and humidity dependent, it can be shown that the distance D to be measured is related to the reference distance D R as follows: i D=D R (1/t R )/(1/t) where t R is the propagation time over the distance D R in the reference unit 12. This relationship is

33、independent of both temperature and humidity. Thus, the outputs of the counters 46 and 78 are provided as inputs to the microprocessor 90 in the utilization means 14. The microprocessor 90 is appropriately programmed to provide an output which is proportional to the ratio of the outputs of the count

34、ers 46 and 78, which in turn are proportional to the repetition rates of the respective trigger pulse trains of the measuring unit 10 and the reference unit 12. As described, this ratio is independent of temperature and humidity and, since the reference distance D R is known, provides an accurate re

35、presentation of the distance D. The utilization means 14 further includes a display 92 which is coupled to and controlled by the microprocessor 90 so that an operator can readily determine the distance D. Experiments have shown that when the distance between the transmitting and receiving transducer

36、s is too small, reflections of the acoustic wave at the transducer surfaces has a not insignificant effect which degrades the measurement accuracy. Accordingly, it is preferred that each transducer pair be separated by at least a certain minimum distance, preferably about four inches. Accordingly, t

37、here has been disclosed improved apparatus for the measurement of distance utilizing ultrasonic waves. While an illustrative embodiment of the present invention has been disclosed herein, it is understood that various modifications and adaptations to the disclosed embodiment will be apparent to thos

38、e of ordinary skill in the art and it is intended that this invention be limited only by the scope of the appended claims.译文超声波测距仪文件类型和数目：美国专利 5442592 摘要：提出了一种超声波测距仪来抵消的影响温度和湿度的变化，包括测量单元和参考资料。在每一个单位，重复的一系列脉冲的产生，每有一个重复率，直接关系到各自之间的距离，发射机和接收机。脉冲提供给各自的主机，和比例的反产出是利用确定的距离被衡量的。 出版日期： 1995 年 8 月 15 日主审查员：罗保

39、.伊恩 j. 一、背景发明本发明涉及到仪器的测量距离，更特别是，这种仪器传送超声波两点之间。 精密机床必须校准。在过去，这已经完成利用机械设备，如卡钳，微米等。不过，使用这种装置并不容易本身自动化技术。据了解，该两点之间距离才能确定通过测量传播时间的浪潮往返那些两点。这样一个类型的波是一种超声波，或声，海浪。当超声波旅行两点之间，距离两个点之间可以衡量乘以过境的时间波由波速，在中期分开两点。因此，这是一个对象本发明提供仪器利用超声波准确测量两点之间距离。 当中等两个点之间的间距是被衡量的是空气，声速是取决于温度和空气相对湿度。因此，它是进一步对象的，现在的发明，提供仪器的类型所描述的是独立于温

40、度和湿度的变化。 二、综述发明前述的和额外的对象是达到了根据这些原则的这项发明提供距离测量仪器，其中包括一个参考的单位和测量单位。参考和测量单位是相同的，每个包括一电发射机和接收机一电。间隔发射器和接收器的参考股是一个固定的参考距离，而间距之间的发射机和接收机的测量单位是距离来衡量。在每一个单位，发射机和接收机是再加上由一个反馈环路导致发射机产生的声脉冲是由接收机和转换成一个电脉冲这是然后反馈到发射机，使重复一系列脉冲的结果。重复率脉冲是成反比关系之间的距离发射器和接收器。在每一个单位，脉冲提供一个反。由于参考的距离是众所周知，比例反产出是利用，以确定所期望的距离来衡量。由于这两方面都是相同的

41、影响，温度和湿度的变化，采取的比例罪状，由此产生的测量变得麻木等变化。 三、简要说明图纸前述将更加明显后，读下列的说明，在与该绘图并在其中单一数字 schematically 描绘仪器兴建根据这些原则的这项发明。 四、详细说明谈到现在的绘图，有结果表明，测量单位和 10 个参考单位 12 个，均加上一个利用的手段14 。测量单位包括 1 10 电发射机 16 日和 1 电接收机 18 。变送器 16 包括压电材料 20 夹心阶层之间的对电极的 22 日和 24 日。同样，接收机 18 个，包括压电材料 26 夹心阶层之间的对电极的 28 日和 30 日。作为众所周知，采用电场整个电极 22 日

42、和 24 日，强调的是，诱导，在压电材料 20 。如果该字段各有不同，如所申请的一个电脉冲，声波是 32 所产生的。为进一步众所周知，当声波影响到接收器 18 ，这诱导应力，在压电材料 26 ，导致一种电信号，以产生全国电极 28 日和 30 日。虽然压电传感器已说明，其他电声装置，可利用，例如，静电，驻极体或电磁类型。 如表所示，电极 28 日和 30 日的接收 18 岁以下的耦合的投入一 34 放大器，其输出耦合输入一个探测器 36 。探测器 36 是安排提供一个信号，脉冲前 38 时，输出放大器 34 已经超过预定的水平。脉冲前 38 ，然后产生一个触发脉冲，这是提供给脉冲发生器 40

43、。在为了提高灵敏度，该系统，传感器 16 和 18 岁以下的共振兴奋。有相应的提供了一个连续波振荡器 42 提供了一个连续振荡信号在一个固定的频率，最好是 共振频率的传感器 16 和18 。这个振荡信号是提供给调制器 44 。要有效地激发发射机 16 ，可取的做法是提供几个周期的共振频率信号，而不是一个单脉冲或单周期。因此，脉冲发生器 40 是安排，在回应的应用存在的一个触发脉冲，提供一个控制脉冲调制器 44 有一个时间的平等的时间，时间预定人数的周期振荡信号从振荡器 42 。这个控制脉冲调制器的原因， 44 个通过了“水管爆裂” 的周期，以激发发射机 16 。 当电力是适用于所描述的电路，有

44、足够的噪音在输入到放大器 34 ，其输出触发脉冲发生器 40 至造成了一片叫好声，振荡周期，以提供整个电极 22 日和 24 日的发射器 16 。变送器 16 因此产生声波 32 条，其中影响到接收器 18 。接收器 18 ，然后产生一个电脉冲，这是适用于输入放大器的 34 ，这再次触发原因的脉冲发生器 40 。这个周期重演，使重复一系列的触发脉冲结果的输出脉冲前 38 。这脉冲列车是应用到 46 个柜位，以及向脉冲发生器 40 。 变送器 16 日和接收 18 岁以下的间隔，除了由距离的 “ D ” ，它是理想的衡量。传播时间的“ T ”为一声波 32 往来变送器 16 日和接收 18 所给

45、予的： = D 的吨/视频 s 凡 v s 是声速在空气中之间的发射机 16 日和接收 18 。柜台 46 措施重复率触发脉冲，这是平等的 1 /汤匙因此，重复率是平等的一至中五的 S /四该声速空气中是一个功能的温度和湿度的空气，内容如下： equ1 其中 T 是温度， P 是局部的压力，水汽， H是该气压， 瓦特和 一顷的比例不断的压力，具体的热不断货量具体的热水汽和干燥的空气，分别。因此，虽然重复率触发脉冲测量非常准确地反 46 ，声速的影响，温度和湿度，使测量的距离 d 无法确定准确。 根据这些原则的这项发明，参考单位提供的是 12 。参考单位 12 是相同的建设为测量单位的 10 个

46、，因此，包括一电发射机 50 个，其中包括压电材料 52 夹心之间的一对电极的54 和 56 ，和一电接收机 58 ，其中包括压电材料 60 夹心阶层之间的一对电极 60,61,62和 64 。再次，传感器以外的其他类型压电可以利用。变送器 50 和接收五十八顷间隔，除了已知的和固定的参考距离“博士” 。电极 60,61,62 和 64 耦合到输入的放大器 66 ，其输出是耦合的投入探测器 68 。输出探测器 68 是耦合的脉搏，前 70 产生触发脉冲。触发脉冲应用到脉冲发生器的 72 个控制调制器 74 通过扫射从连续波振荡器 76 至变送器 50 。触发脉冲从脉冲前 70 也适用于反 78

47、 。 最好是，所有的传感器 16 ， 18 ， 50 和 58 具有相同的 共振频率。因此，振荡器 42 和76 都在运作，频率和脉冲发电机 40 和第 72 条提供平等的输出脉冲宽度。 在用法上，测量装置 10 和参考资料股一十二顷在接近，使该声速在这两个单位是相同的。虽然留级率的脉冲在测量单位， 10 和参考资料股十二顷每个温度和湿度的依赖性，能证明的距离 D 来衡量。 其中 T R 是传播时间超过距 离博士在参考股 12 。这种关系是独立于双方的温度和湿度。因此，产出的柜台 46 和 78 所提供的投入微处理器的 90 个利用的手段 14 。微处理器90 是适当的程序提供了一个输出是成正

48、比的比例，产出的柜台 46 和 78 ，这反过来又是成正比的重复率分别触发脉冲列车的测量单位， 10 和参考资料股 12 。作为描述，这个比例是独立的温度和湿度，由于参考的距离，博士，是众所周知的，提供了一个准确的代表性距离四，利用手段， 14 日还包括一个显示 92 这是耦合和控制的微处理器，使 90 一个经营者可以随时确定的距离四实验表明，当之间的距离发射和接收传感器是太小了，思考的声波在传感器的表面有一个不小的作用，降低了测量精度。因此，最好是每换一双分开，至少由某一个最小距离，最好是约四英寸。 因此，已披露的改善仪器的测量距离，利用超声波。而一个说明性的体现，本发明已披露者外，据了解，各种修改和适应所披露的体现，将是显而易见的那些普通的技巧与艺术，这是打算把这个发明只限于由范围所附的索赔。